# import numpy as np
import sys, math
from itertools import permutations, combinations
from collections import defaultdict, Counter, deque
from math import factorial  # , gcd
from bisect import bisect_left, bisect_right  # bisect_left(list, value)

sys.setrecursionlimit(10 ** 7)
enu = enumerate
MOD = 10 ** 9 + 7
input = lambda: sys.stdin.readline()[:-1]
pl = lambda x: print(*x, sep="\n")

X = int(input())
print('Yes') if 30<=X else print('No') import sys, math sys math from itertools import permutations, combinations from collections import defaultdict, Counter, deque from math import factorial from bisect import bisect_left, bisect_right sys.setrecursionlimit(10 ** 7) sys.setrecursionlimit sys setrecursionlimit 10 ** 7 10 7 enu = enumerate enu enumerate MOD = 10 ** 9 + 7 MOD 10 ** 9 + 7 10 ** 9 10 9 7 input = lambda: sys.stdin.readline()[:-1] input lambda: sys.stdin.readline()[:-1] sys.stdin.readline()[:-1] sys.stdin.readline() sys.stdin.readline sys.stdin sys stdin readline :-1 -1 pl = lambda x: print(*x, sep="\n") pl lambda x: print(*x, sep="\n") print(*x, sep="\n") print *x x sep="\n" sep "\n" x X = int(input()) X int(input()) int input() input print('Yes') if 30<=X else print('No') 30<=X 30 X print('Yes') print 'Yes' print('No') print 'No' pl = lambda x: print(*x, sep="\n") lambda x: print(*x, sep="\n") pl enu = enumerate enumerate enu MOD = 10 ** 9 + 7 10 ** 9 + 7 MOD X = int(input()) int(input()) X input = lambda: sys.stdin.readline()[:-1] lambda: sys.stdin.readline()[:-1] input
# import numpy as np
import sys, math
from itertools import permutations, combinations
from collections import defaultdict, Counter, deque
from math import factorial  # , gcd
from bisect import bisect_left, bisect_right  # bisect_left(list, value)

sys.setrecursionlimit(10 ** 7)
enu = enumerate
MOD = 10 ** 9 + 7
input = lambda: sys.stdin.readline()[:-1]
pl = lambda x: print(*x, sep="\n")

X = int(input())
print('Yes') if 30<=X else print('No')